docs: def unitim(epoch, insys, outsys):
      """
      Transform time from one uniform scale to another.  The uniform
      time scales are TAI, TDT, TDB, ET, JED, JDTDB, JDTDT.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/unitim_c.html
  
      :param epoch: An epoch to be converted.
      :type epoch: float
      :param insys: The time scale associated with the input epoch.
      :type insys: str
      :param outsys: The time scale associated with the function value.
      :type outsys: str
      :return:
              The float in outsys that is equivalent
              to the epoch on the insys time scale.
      :rtype: float
      """
      epoch = ctypes.c_double(epoch)
      insys = stypes.stringToCharP(insys)
      outsys = stypes.stringToCharP(outsys)
      return libspice.unitim_c(epoch, insys, outsys)